Enhanced time-aware QoS prediction in multi-cloud: a hybrid k-medoids and lazy learning approach (QoPC)

Cloud service providers should be able to predict the future states of their infrastructure in order to avoid any violation of Service Level Agreement. This becomes more complex when vendors have to deal with services from various providers in multi-clouds. As a result, QoS prediction can significantly support service providers in a better understanding of their resources future states. Users should also be very well aware of their resource needs, as well as the Quality of Service relative values. This paper proposes a hybrid approach to the prediction of the future value of the QoS features. The hybrid approach uses a modified version of k-medoids algorithm for the clustering of large time-series datasets, as well as a proposed algorithm inspired from the lazy learning and lower bound Dynamic Time Warping (LB-Keogh) for pruned DTW computations. The proposed method in this manuscript is a shape-based QoS prediction with a novel pre-processing method, which fulfills the missing data with statistically semi-real data. In order to solve the cold start problem, we proposed new algorithm based on the DTW Barycenter Averaging (DBA) algorithm. The results showed that our predicted values are very close to real values and achieve only 0.35 of the normalized mean absolute error rate, on average, for the WSDream dataset and 0.07 for the Alibaba dataset.